KRB-5404
28
Fig. 20 provides the terminal arrangement of the ACB.
Position switches
Auxiliary switches
(When 4C is used)
(When standard 4C + optional 6C are used)
Upper stage
Middle stage
Lower stage
(When 2C is used)
(When standard 4C is used)
Upper stage
Middle stage
Lower stage
(Com. terminals)
Control/operation circuit
The communication terminal block is added when the
undervoltage trip device and the separate N-phase CT
are used or the zone interlock, external indication or
communication capability is provided.
Fig. 20 Terminal arrangement
Fig. 21 shows how to connect the line side ground fault protection (REF) CT when the overcurrent release (OCR) is provided with
the REF capability. See Fig. 19 for other circuits than that of the line side ground fault protection CT.
Fig. 21 Connection of the line side ground fault protection (REF) CT
Fig. 22 shows how to connect ACBs when the overcurrent release (OCR) is provided with the zone interlock (Z) capability. See Fig.
19 for other circuits than that of the zone interlock.
*1
Zone interlock requires control power (DC24V) between
□
33
and
□
34
.
*2
Zone interlock capabilities for shot time delay trip and for
ground fault can be combined.
*3
The zone interlock system allows selective discrimination that,
when a fault current higher than the short time delay trip or
ground fault trip pickup current is detected at a point in the
power distribution system, operates the upstream ACB nearest
to the point to shut off power within 50 ms even if the
instantaneous trip function is set to NON, thus minimizing
thermal and mechanical damage to the power distribution
system. (The zone interlock system uses breaker 1, 2, …n to
shut off power when a fault current is detected in zone 1, 2, …n
within 50 ms.)
*4
Up to eight ACBs can be connected in the zone interlock
system. Connect the uppermost ACB as ACB 1 and the
lowermost ACB as ACB n, assuming the number of ACBs is n.
*5
The zone interlock cable should be of four-core, twisted pair
shield type (Showa LW222S or equivalent).
*6
Max. length pf cables
○
1
and
○
3
: 300 m
Fig. 22 Zone interlock (Z) connections
○
1
Zone interlock connection between ACBs for short time delay trip
○
2
Zone interlock connection of the lowermost ACB for short time delay trip
○
3
Zone interlock connection between ACBs for ground fault trip
○
4
Zone interlock connection of the lowermost ACB for ground fault trip
